Bicycle rear suspension

ABSTRACT

A bicycle frame assembly having a main frame and an articulating frame supported for movement relative to the main frame. The articulating frame is configured to carry a rear wheel for rotation about a hub axis. A shock absorber is operably connected between the main frame and the articulating frame to provide resistance to articulating motion of the articulating frame. The articulating frame includes a chain stay member and a shock support member fixed for angular displacement with the chain stay member.

PRIORITY INFORMATION

This application claims priority from Provisional Patent Application No.60/473,500 filed May 27, 2003, the entire contents of which are herebyincorporated by reference herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to vehicle suspension systems.More particularly, the present invention relates to a rear wheelsuspension assembly suitable for use in connection with off-roadbicycles.

2. Description of the Related Art

Off-road bicycles, or mountain bikes, may be equipped with front andrear suspension assemblies operably positioned between the front andrear wheels, respectively, and the frame of the bicycle. Providing frontand rear suspension on a mountain bike potentially improves handling andperformance by absorbing bumps, and other rough trail conditions, whichmay be encountered while riding off-road. As the sport of mountainbiking has evolved, the size and difficulty of the obstacles that havebecome commonplace has increased in scale. As a result, bicyclemanufacturers have attempted to continually increase the amount ofsuspension travel, or the distance that the front and rear wheels maymove relative to the frame, of their respective all-purpose mountainbikes.

For comfort, performance and handling reasons, it is desirable to limitthe size of a bicycle frame in both longitudinal (lengthwise) andlateral directions. As a result, only a limited amount of space isavailable before the bicycle becomes too long or too wide. As the amountof suspension travel increases, it becomes more difficult to achieve theperformance objectives of the suspension assembly (e.g., isolating pedaland brake forces, providing a desired leverage rate or rate progression,etc.) while also accommodating necessary or desired features orcomponents of the bicycle (e.g., a movable front derailleur, waterbottle cages, etc.) within the available space.

One common bicycle rear suspension design involves a single lever, orswingarm, supporting a rear wheel at one end and being pivotallyconnected to the bicycle frame at the other end. Although such a systemis simple and reliable, the single lever, or single pivot, rearsuspension design suffers from a relatively large amount of pedal forcesand braking forces being transmitted into the rear suspension assembly.Furthermore, in order to provide a large amount of suspension travel, itis necessary to increase the length of the swingarm. Practicalconstraints, such as limiting the overall length of the bicycle,necessitates placing the pivot for the single lever in a positionforward of the pedal crank assembly of the bicycle. As a result, theswingarm typically passes above the pedal crank axis, through a locationwhere the front derailleur would normally be placed. As a result, manysingle pivot, long travel rear suspension bicycles are prevented fromutilizing a front derailleur, which severely limits the number of gearratios available to the rider.

Rear suspension designs that include multiple lever members and,therefore, multiple pivots, typically exhibit better isolation ofpedaling forces and braking forces from the rear suspension. Typically,a multiple lever rear suspension assembly will have a pair of lower arms(i.e., chain stays) pivotally connected to the bicycle frame at aforward end and a link member pivotally mounted to the main frame at alocation above the chain stays. A pair of rearward arms (i.e., seatstays) are pivotally connected between rearward ends of the chain staysand link member. The rear wheel may be carried by either of the chainstays or seat stays. Typically, the rear shock absorber is operablypositioned between the link member and the main frame. As a result,placement of the shock absorber is at a relatively high position withinthe bicycle frame, thereby raising the overall center of gravity of thebicycle, which is detrimental to the handling qualities of the bicycle.This drawback is magnified in large suspension travel designs, whereinthe size of the rear shock absorber is typically increased.

One proposed solution is to extend a forward end of the link memberbeyond the seat tube of the main frame and mount the shock absorber in agenerally vertical arrangement in front of the seat tube. However, sucha design necessitates the use of a long link member, which then mustalso be increased in size in order to resist bending or torsionalforces. The large link member offsets a substantial portion of thelowered center of gravity benefit of the lowered shock position. Inaddition, the elongated link member increases the lever arm of forcesintroduced into the suspension assembly through the rear wheel. As aresult, a large amount of force is applied to the main frame by thelever, which necessitates enlarging and/or reinforcing the main frame tohandle these stresses. In addition, the placement of the shock absorberadjacent the seat tube typically precludes the use of a frontderailleur.

SUMMARY OF THE INVENTION

Accordingly, a need exists for an improved rear suspension designespecially well suited for use in long travel arrangements, such asthose bicycles providing more than about 6 inches of rear suspensiontravel, for example. Although, preferably, such a rear suspension designwould also be well suited for use with bicycles having less than 6inches of rear suspension travel. Furthermore, it is desirable that theimproved rear suspension design is configured to permit the use of amovable front derailleur and, thereby, increase the range of gearingavailable to the rider. It is also desirable that such a rear suspensiondesign provides a bicycle frame with a low center of gravity andprovides good isolation of pedal forces and braking forces from the rearsuspension. A preferred rear suspension assembly desirably achieves one,or more, of these preferred characteristics.

A preferred embodiment involves a bicycle frame including a main frameand an articulating frame. The main frame defines a steering axis and isconfigured to support a front wheel for rotation about the steeringaxis. The articulating frame is configured to support a rear wheelrelative to the main frame. The articulating frame includes a chain staymember and a shock support member. The chain stay member is pivotallysupported relative to the main frame and the shock support member isfixed for angular displacement with the chain stay. A shock absorber hasa first end pivotally supported at a first axis by the shock supportmember and a second end pivotally supported at a second axis by the mainframe. The first axis is positioned above the second axis such that alongitudinal axis of the shock absorber slopes downwardly from the firstend to the second end. Preferably, the main frame is configured tosupport a pedal crank assembly for rotation about a crank axis.Desirably, the first axis is positioned behind the crank axis and thesecond axis is positioned in front of the crank axis.

A preferred embodiment involves a bicycle frame including a main frame,which defines a steering axis and is configured to support a front wheelfor rotation about the steering axis. A chain stay member is pivotallysupported relative to the main frame at a first pivot axis. A linkmember is pivotally supported by the main frame at a second pivot axis.A seat stay member is pivotally supported by the chain stay member at athird pivot axis and by the link member at a fourth pivot axis. A shocksupport member is fixed for angular displacement with the chain staymember and defines a derailleur-mount portion configured to support afront derailleur in an operable position relative to a pedal crankassembly carried by said main frame. A shock absorber is pivotallysupported by the shock support member at a fifth pivot axis and by themain frame at a sixth pivot axis.

A preferred embodiment involves a bicycle having a front wheel, a rearwheel and a main frame. The main frame defines a steering axis and isconfigured to support the front wheel for rotation about the steeringaxis. The bicycle also includes an articulating frame configured tosupport the rear wheel relative to the main frame. The articulatingframe includes a chain stay member and a shock support member. The chainstay member is pivotally supported relative to the main frame and theshock support member is fixed for angular displacement with the chainstay member. A shock absorber has a first end pivotally supported at afirst axis by the shock support member and a second end pivotallysupported at a second axis by the main frame. The first axis ispositioned above the second axis such that a longitudinal axis of theshock absorber slopes downwardly from the first end to the second end.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presentinvention are described below with reference to drawings of preferredembodiments, that are intended to illustrate, but not to limit, thepresent invention. The drawings contain five figures.

FIG. 1 is a side elevational view of an off-road bicycle, or mountainbike, incorporating a bicycle frame having certain features, aspects andadvantages of the present invention.

FIG. 2 is a side elevational view of the bicycle frame of FIG. 1 withcertain components of the bicycle removed for the purpose of clarity.

FIG. 3 is a schematic illustration of the bicycle frame of FIG. 1.

FIG. 4 is a schematic illustration of a modification of the bicycleframe of FIG. 1.

FIG. 5 is a schematic illustration of another modification of thebicycle frame of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates an off-road bicycle, or mountain bike 10, including apreferred rear suspension assembly. The bicycle 10 is described hereinwith reference to a coordinate system wherein a longitudinal axisextends from a forward end to a rearward end of the bicycle 10. Avertical, central plane generally bisects the bicycle 10 and containsthe longitudinal axis. A lateral axis extends normal to the longitudinalaxis and lies within a horizontal plane. In addition, relative heightsare generally expressed as elevations from a horizontal surface S uponwhich the bicycle 10 is supported in an upright position. Similarly,relative forward and rearward positions are expressed as distances froma vertical axis, which is normal to the horizontal surface S. Theabove-described coordinate system is provided for the convenience ofdescribing the embodiment illustrated in FIGS. 1–5, and is not intendedto limit the scope of the present invention unless expressly indicated.

The bicycle 10 includes a frame assembly 12 comprised of a main frame 14and an articulating frame, or sub-frame 16, pivotally supported relativeto the main frame 14. The bicycle 10 also includes a front wheel 18carried by a front suspension assembly, or suspension fork 20. A steerertube (not shown) is journaled for rotation about a steering axis A_(S)defined by the main frame 14. A handlebar assembly 22 is connected to anupper end of the suspension fork 20 and is operable to permit a rider ofthe bicycle 10 to rotate the front wheel 18 about the steering axisA_(S).

A rear wheel 24 of the bicycle 10 is carried by the subframe 16. A shockabsorber 26 is pivotally connected to both the main frame 14 and thesubframe 16 to provide resistance to articulating motion of the subframe16 relative to the main frame 14 and, thus, provide resistance to thesuspension travel of the rear wheel 24. A seat assembly 28 is supportedabove the bicycle frame 12 at a position behind the handlebar assembly22 and provides support for a rider of the bicycle 10.

A pedal crank assembly 32 is rotatably supported by the bicycle frame 12and drives a multi-speed chain drive arrangement 34. The multi-speedchain drive arrangement 34 preferably includes a plurality of sprockets,or chain rings 36, rotatably connected to the pedal crank 32. Typically,three chain rings 36 of varying size are mounted to the pedal crank 32.The chain drive arrangement 34 also includes a plurality of sprockets,or cogs 38, drivingly coupled to the rear wheel 24. A drive chain 40drivingly interconnects a selected chain ring 36 with a selected cog 38to transfer torque from the pedal crank assembly 32 to the rear wheel24. Preferably, front and rear derailleurs 42, 44 are supported by thebicycle frame 12 and are configured to move the drive chain 40 to aselected one of the chain rings 36 and rear cogs 38, respectively.

The bicycle 10 also includes front and rear brake systems 46, 48 forslowing and stopping the bicycle 10. Although the illustrated brakes 46,48 are disc-type brakes, other suitable brake systems may also be used,such as rim-type brakes for example. Rider controls (not shown) aretypically provided on the handlebar assembly 22 and are operable tocontrol shifting of the front and rear derailleurs 42, 44 and the frontand rear brake systems 46, 48.

With reference to FIG. 2, the bicycle frame 12 and rear shock absorber26 are illustrated with the remaining components of the bicycle 10removed for clarity. As described above, preferably, the bicycle frame12 is primarily comprised of a main frame 14 and an articulating frame,or subframe 16. The main frame 14 includes a head tube 50 which definesthe steering axis A_(S) of the bicycle frame 12. Desirably, the steeringaxis A_(S) is canted rearwardly from a vertical axis. The head tube 50is configured to rotatably support the front suspension 20 and, thus,the front wheel 18 of the bicycle 10.

A top tube 52 and a down tube 54 extend in a rearward direction from thehead tube 50 and diverge from one another when moving toward theirrearward ends. A bottom bracket support member 56 extends between therearward ends of the top tube 52 and the down tube 54 and togethertherewith defines a generally triangular shape. The bottom bracketsupport member 56 includes a bottom bracket shell 58, which supports thepedal crank assembly 32 (FIG. 1) for rotation about a crank axis A_(C).

A seat tube 60 extends in an upward direction from a rearward end of thetop tube 52 and, preferably, is canted rearwardly from a vertical axis.The seat tube 60 supports the seat assembly 28 shown in FIG. 1.Desirably, a gusset 62 extends from a forward side of the seat tube 60to an upper side of the top tube 52 to provide additional strength tothe seat tube 60.

Preferably, the main frame 14 is constructed of individual components,as described above, which are fabricated from a metal material, such asaluminum or steel, and welded together. Desirably, the bottom bracketsupport member 56 is created from a metal material by a forging processand, thus, benefits from the strength and durability advantages thatinherently result from the forging process. Preferably, the articulatingframe 16 and the shock absorber 26 are directly supported by the bottombracket support member 56, as is described in greater detail below.

However, in alternative embodiment, the main frame 14 may be constructedin a more conventional fashion wherein the forged bottom bracket supportmember 56 is omitted and the articulating frame 16 and shock absorber 26may be pivotally connected to the welded-up tubes comprising the mainframe 14. Further, other suitable constructions of the main frame 14,including non-triangular constructions, may also be used, such as amonocoque construction, for example. In addition, alternative materialssuch as composites may also be used in whole or in part to construct themain frame 14, as will readily be appreciated by one of skill in theart. The illustrated embodiment is preferred, however, for at least thereasons discussed herein.

As described above, the illustrated bicycle frame 10 includes a shockabsorber 26 operably positioned between the main frame 14 and thesubframe 16. Desirably, the shock absorber 26 is configured to provideboth a spring force and a damping force in response to relative movementbetween the subframe 16 and the main frame 14, as is known in the art.The spring force is related to the relative position between thesubframe 16 and the main frame 14 while the damping force is related tothe relative speed of movement between the subframe 16 and the mainframe 14.

Although the illustrated shock absorber 26 incorporates a coil typespring 64, other suitable suspension springs, such as air springs, forexample, may also be used. Preferably, the damping system comprises apiston movable within a fluid cylinder of the shock absorber 26.Desirably, the piston forces hydraulic fluid within the fluid chamberthrough one or more restrictive flow paths to generate a damping forcewhen the shock absorber 26 is both extending and compressing, as isknown in the art. In addition, other types of damping arrangements, suchas inertia activated and position sensitive arrangements, may also beused, as well be readily understood by one of skilled in the art.

As described above, the subframe 16 is configured to support the rearwheel 24 (FIG. 1) for a movement throughout a suspension travel pathrelative to the main frame 14 from a relaxed position, substantially asillustrated in FIG. 2, to a compressed position, wherein the subframe 16is pivoted in an upward direction relative to the main frame 14.Preferably, the subframe 16 is a multiple linkage assembly. That is,preferably, the subframe 16 includes a plurality of linkage memberspivotally interconnected with one another. However, in alternativearrangements, a single link member may carry the rear wheel 24 formovement in a simple, arcuate suspension travel path relative to themain frame 14.

In the illustrated arrangement, the subframe 16 includes a chain staymember 70 having a forward end 70 a pivotally connected to the mainframe 14 for rotation about a pivot axis 72 a. Preferably, the chainstay member 70 includes a pair of laterally-space arms that extend in arearward direction from the forward end 70 a and straddle the rear wheel24 (FIG. 1). However, in an alternative arrangement, the chain staymember 70 may comprise a single arm positioned on one side of the rearwheel 24. Desirably, the chain stay member 70 is connected directly tothe main frame 14. However, alternatively, the chain stay member 70 maybe connected to the main frame 14 indirectly, such as through anadditional link member, for example.

A link member, or lever arm 74, is pivotally connected at a forward end74 a to the main frame 14 for a pivotal motion about a pivot axis 72 b.Desirably, the pivot axis 72 b is spaced above the pivot axis 72 a and,preferably, is positioned proximate a junction between the seat tube 60and the top tube 52. In the illustrated embodiment, a forward end 74 aof the link member 74 includes a pair of arm portions straddling theseat tube 60.

A seat stay member 76 is pivotally supported at an upper end 76 a by arearward end 74 b of the link member 74 for pivotal movement about apivot axis 72 c. A lower end 76 b of the seat stay member 76 ispivotally supported at a pivot axis 72 d defined by a rearward end 70 bof the chain stay member 70. Preferably, the seat stay member 76includes a pair of laterally-spaced arms straddling the rear wheel 24(FIG. 1) and interconnected by a bridge 78 at the upper end 76 a of theseat stay member 76.

A shock support member 80 is fixed for rotation with the chain staymember 70. Thus, any given point on the shock support member 80 rotatesthrough the same angular displacement about the pivot axis 72 a as anypoint on the chain stay member 70. Preferably, the shock support member80 includes a forward arm 82 and a rearward arm 84. Desirably, theforward arm 82 extends in an upward, and slightly rearward, directionfrom a forward end 70 a of the chain stay member while the rearward arm84 extends in an upward and forward direction from a rearward end 70 bof the chain stay member 70. The forward and rearward arms 82, 84 arejoined at their upper ends such that the forward arm 82, the rearwardarm 84 and chain stay member 70 form a generally triangular shape whenviewed from a side of the bicycle frame 12. Such a triangulararrangement provides a shock support member 80 having an advantageouslyhigh strength to weight ratio. However, other suitable arrangements ofthe shock support member may also be used, such as a single arm, with orwithout additional supports, such as gussets, for example.

Preferably, the rearward arm member 84 includes a pair oflaterally-spaced arm portions configured to straddle the rear wheel 24(FIG. 1) and being interconnected at their upper ends. Preferably, theforward arm 82 is positioned in front of and generally in the same planewith the rear wheel 24.

Desirably, a front end 26 a of the shock absorber 26 is pivotallyconnected to the main frame 14 and, more specifically, to the bottombracket support member 56 for rotation about a pivot axis 86. A rearwardend 26 b of the shock absorber is pivotally connected to the shocksupport member 80 near a junction of the forward arm 82 and the rearwardarm 84 for rotation about a pivot axis 88. Advantageously, theillustrated shock support member 80 positions an rearward end 26 b ofthe shock absorber 26 at a relative position configured to accommodatethe rear wheel 24 without requiring an increase in the overall length ofthe frame. Preferably, the pivot axis 88 of the rearward end 26 a of theshock absorber 26 is spaced from the hub axis A_(H) a radial distance ofat least about 26 inches in order to accommodate a rear wheel 24 of atypical diameter. However, the positioning of the pivot axis 88 may alsobe configured to accept larger wheels. Furthermore, in order toaccommodate a shock absorber 26 of a desired length, preferably, thepivot axis 88 is positioned a radial distance from the crank axis A_(C)of between about 6 and 10 inches and, more preferably, about 8 inches.

In one typical prior art arrangement, the shock absorber 26 is connectedto the link member 74 and extends forwardly and upwardly to the mainframe 14. In another prior art arrangement, the shock absorber 26 issituated in a substantially vertical orientation in front of the seattube 60. However, in the presently illustrated arrangement, the forwardend 26 a of the shock absorber is positioned relatively lower than therearward end 26 b of the shock absorber. Furthermore, the rearward end26 b of the shock absorber 26 is supported by the shock support member80 at a position below the link member 74. Thus, the shock absorber 26is mounted at a significantly lower position within the bicycle frame 12than in the prior art arrangements. Accordingly, the illustratedarrangement provides a significantly lower center of gravity of thebicycle frame 12 than prior art arrangements, which improves handlingcharacteristics of the associated bicycle 10.

As described above, the forward end 26 a of the shock absorber 26 ispositioned relatively lower than the rearward end 26 b. Thus, the pivotaxis 86 is positioned relatively lower than the pivot axis 88. Thus, alongitudinal axis of the shock absorber 26 is canted in a downwarddirection when moving from the rearward end 26 b toward the forward end26 a of the shock absorber 26. In addition, preferably, the pivot axis86 and the pivot axis 88 straddle the crank axis A_(C). That is, theforward end 26 a and forward pivot axis 86 of the shock absorber 26 arepositioned forwardly of the crank axis A_(C) while a rearward end 26 band a rearward pivot axis 88 of the shock absorber 26 are positionedrearwardly of the crank axis A_(C). Preferably, the forward pivot axis86 of the shock absorber 26 is positioned between about 4 and 12 inchesfrom the crank axis A_(C) and, more preferably, between about 5 and 7inches from the crank axis A_(C).

Accordingly, with such a construction, a relatively long shock absorber26 may be accommodated in a relatively low position without resulting ina lengthening of the bicycle frame 12. In a long travel bicycle frame,it is desirable to provide a shock absorber of a relatively increasedlength in order to retain a desirable ratio between movement of the rearwheel and corresponding movement (i.e., compression or rebound movement)of the shock absorber. If the ratio of wheel movement to shock absorbermovement is increased, the force transmitted to the shock absorber isincreased, which must be offset by higher spring and damping rates ofthe shock absorber. The higher spring and damping rates result in areduction in the ride characteristics of the shock absorber. Thus, theillustrated rear suspension assembly is capable of accommodating asuitably-sized shock absorber 26 in order to maintain a desirable ratiobetween movement of the rear wheel 24 and movement of the shock absorber26.

In addition, the illustrated bicycle frame 12 is arranged to achieve theabove-described objects without precluding the use of a front derailleur42 (FIG. 1). The use of a front derailleur 42 has long been a problemwith bicycles having a relatively large amount of rear wheel travel dueto either the position of the swingarm pivot, in a single pivotarrangement, or due to interference with the chain stay member 70 and/orshock absorber 26 in multi-pivot arrangements.

In the illustrated bicycle frame 12, the pivot axis 72 a between thechain stay member 70 and shock support member 80 and the main frame 14is positioned in a relative close proximity to the crank axis A_(C).Desirably, the pivot axis 72 a is positioned within a radial distance ofthe crank axis A_(C) of less than about 3 inches and, more desirably, ofless than about 2 inches. Furthermore, the forward arm 82 of the shocksupport member 80 defines a derailleur mount portion 90 configured toaccept the front derailleur 42 (FIG. 1). Thus, the front derailleur 42is fixed for movement with the subframe 16 and more specifically withthe chain stay member 70 and shock support member 80.

Because the pivot axis 72 a, about which the shock support member 80pivots is positioned in relatively close proximity to the crank axisA_(C), the front derailleur 42 remains in an operable position relativeto the chain rings 36 of the pedal crank assembly 32 (FIG. 1) throughoutthe suspension travel of the subframe 16. Furthermore, common frontderailleurs 42 are configured to be positioned in an upper, rearwardposition relative to the chain rings 36, as illustrated in FIG. 1.Advantageously, because the pivot axis 72 a is positioned to a rearwardside of the crank axis A_(C), the front derailleur 42 remains closer tothe chain rings 36 than if the swing arm pivot were to be located infront of the crank axis A_(C), as is common in long travel single pivotbicycle frames.

Preferably, the pivot axes 72 a and 72 b along with the shock pivot axis86 are all defined by the bottom bracket support member 56. As describedabove, desirably the bottom bracket support member 56 is constructed ofa monolithic, forged piece of material. Accordingly, the bottom bracketsupport member 56 may take on a more complex structure than the typicalwelded together tubes of a conventional bicycle frame. Advantageously,the monolithic bottom bracket support member 56 can be configured tohandle the specific loads placed on the main frame 14 by the subframe 16with a minimum of material, thereby resulting in a wider overall weightof the bicycle frame 12. In addition, due to the high strength of thebottom bracket support member 56, the seat tube 60, top tube 52 and downtube 54 do not have to support the loads placed on the main frame 14 bythe subframe 16 and, therefore, can be lighter in weight.

Preferably, the seat stay member 76 supports the rear wheel 24 (FIG. 1)for rotation about a hub axis A_(H) and, preferably, the hub axis A_(H)is positioned above the pivot axis 72 d defined by the lower end 76 b ofthe seat stay member 76 and the rearward end of the chain stay member.Accordingly, the suspension path of the hub axis A_(H) is determinedprimarily by the relative lengths and angles of the link member 74 andthe seat stay member 76. Desirably, the hub axis A_(h) moves through agenerally vertical wheel path in order to inhibit pedal forces orbraking forces from influencing movement of the rear wheel 24 throughoutthe suspension travel path. However, in alternative arrangements, thehub axis A_(H) may move through a more complex, curvilinear wheel path.As described above, the illustrated bicycle frame 12 is well adapted toprovide a relatively large amount of rear wheel 24 suspension travel.Preferably, the frame 12 provides at least about 6 inches of verticalmovement of the hub axis A_(h) relative to the main frame 14 and, morespecifically, relative to the surface S upon which the bicycle 10 isbeing ridden. More preferably, the hub axis A_(H) is configured for atleast about 8 inches of vertical movement. As will be readilyappreciated by one of skill in the art, the movement of the hub axisA_(H) is dependent on the overall position of the bicycle 10 and,therefore, may not necessarily be vertical. Herein, the term “vertical”is used in reference to the position of the bicycle 10 illustrated inFIG. 1. The “vertical” movement of the hub axis A_(H) may also bedescribed as movement substantially normal to the surface S.

Furthermore, in the illustrated bicycle frame 12, the rear shockabsorber 26 is actuated by the shock support member 80, which is fixedfor rotation with the chain stay member 70. Thus, an existing,relatively long lever arm (i.e., the chain stay member 70) is utilizedto actuate the shock absorber 26 and, therefore, primarily influencesthe rate of progression of the leverage, or mechanical advantage, thatthe lever arm (chain stay member 70) has in acting on the rear shockabsorber 26. Thus, with the preferred arrangement illustrated herein,leverage ratio on the shock absorber 26 is determined primarily by thechain stay member 70 (through the shock support member 80) while thewheel path is primarily determined by the link member 74 and the seatstay 76. Accordingly, each of the leverage ratio and the wheel pathcharacteristics may be optimized.

FIG. 3 is a schematic illustration of the bicycle frame 12 of FIGS. 1and 2. FIG. 3 presents a simplified illustration of the members 70, 74,76, 80 of the subframe 16 in order to enable a comparison withadditional preferred embodiments. Preferably, as described above, thehub axis A_(H) is defined by the seat stay member 76, which is supportedrelative to the main frame 14 by the link member 74 and the chain staymember 70. In addition, preferably, the shock support member 80 supportsthe shock absorber 26, along with the main frame 14, such that thelongitudinal axis A_(r) of the shock absorber 26 defines an angle θ ofbetween about 0 degrees and 45 degrees relative to the surface S uponwhich the bicycle 10 (FIG. 1) rests. More preferably, the angle θ isbetween about 15 and 25 degrees and, most preferably, is about 20degrees. As described above, such an arrangement permits theaccommodation of a shock absorber 26 of a desirable length and lowersthe center of gravity of the frame 12, without increasing the overalllength of the frame 12.

FIG. 4 illustrates a modification of the bicycle frame 12 of FIGS. 1through 3 and is generally referred to by the reference numeral 12′. Thebicycle frame 12′ is similar to the bicycle frame 12 of FIGS. 1 through3 and, therefore, like reference numerals will be used to indicate likecomponents, except that a prime (′) has been added.

The bicycle frame 12′ is an operable, although less preferred,construction having a main frame 14′ and a subframe 16′. The main frame14′, preferably, is substantially similar to the main frame 14 of FIGS.1 through 3. The subframe 16′ is similar to the subframe 16 of FIGS. 1through 3 with the exception that the hub axis A_(H) and, thus, the rearwheel are carried by the chain stay member 70′, instead of the seat staymember 76′. As a result, the hub axis A_(H) moves in a simple arcuatepath about the chain stay pivot 72 a. Such a construction is lesseffective at isolating pedal forces and braking forces from influencingmovement of the subframe 16′ relative to the main frame 14′.

FIG. 5 illustrates yet another modification of the bicycle frame 12 ofFIGS. 1 through 3 and is generally referred to by the reference numeral12″. The bicycle frame 12″ is similar to the bicycle frame 12 of FIGS. 1through 3 and, therefore, like reference numerals are used to indicatelike components, except that a double prime (″) has been added.

The bicycle frame 12″ also includes a main frame 14″, preferablyconstructed in a manner similar to the main frame 14, and a subframe 16″supported for movement relative to the main frame 14″. The subframe 16″includes a shock support member 80″ is fixed for movement with the chainstay member 70″, as in the frame 12 of FIGS. 1–3. However, the chainstay member 70″ is elongated and connected to the seat stay member 76″at a position above the hub axis A_(H). As in the frame 12 of FIGS. 1–3,the shock absorber 26″ is actuated by the shock support member 80″,which is fixed to the chain stay member 70″ and the hub axis A_(H) isdefined by the seat stay member 76″.

Although the present invention has been disclosed in the context ofseveral preferred embodiments, it will be understood by those of skilledin the art that the scope of the present invention extends beyond thespecifically disclosed embodiments to alternative embodiments and/oruses of the invention and obvious modifications and equivalents thereof.Accordingly, the invention is intended to be defined solely by theappended claims.

1. A bicycle frame, comprising: a main frame, said main frame defining asteering axis of said bicycle frame and being configured to support afront wheel for rotation about said steering axis; an articulating frameconfigured to support a rear wheel relative to said main frame, saidarticulating frame comprising a chain stay member and a shock supportmember, said chain stay member being pivotally supported relative tosaid main frame and said shock support member being fixed for angulardisplacement with said chain stay member; a shock absorber having afirst end and a second end, said first end being pivotally supported ata first axis by said shock support member and said second end beingpivotally supported at a second axis by said main frame; wherein saidfirst axis is positioned above said second axis such that a longitudinalaxis of said shock absorber slopes downwardly from said first end tosaid second end.
 2. The bicycle frame of claim 1, wherein said mainframe is configured to support a pedal crank assembly for rotation abouta crank axis, said first axis being positioned behind said crank axisand said second axis being positioned in front of said crank axis. 3.The bicycle frame of claim 1, wherein said shock support membercomprises a first arm and a second arm extending from said chain staymember toward said first axis, said first arm, said second arm and saidchain stay member cooperating to form a generally triangular shape whenviewed from the side of said bicycle frame.
 4. The bicycle frame ofclaim 1, wherein said chain stay member is pivotally connected directlyto said main frame.
 5. The bicycle frame of claim 1, wherein saidarticulating frame additionally comprises a seat stay member and a linkmember, said link member being pivotally connected to said main frameand said seat stay member being pivotally connected to each of saidchain stay member and said link member.
 6. The bicycle frame of claim 5,wherein said rear wheel is supported for rotation about a hub axis, saidhub axis being defined by said seat stay member.
 7. The bicycle frame ofclaim 6, wherein said pivotal connection between said chain stay memberand said seat stay member is positioned above said hub axis on said seatstay member.
 8. The bicycle frame of claim 5, wherein said rear wheel issupported for rotation about a hub axis, said hub axis being defined bysaid chain stay member.
 9. The bicycle frame of claim 5, wherein saidshock support member defines a derailleur-mount portion configured tosupport a front derailleur in an operable position relative to a pedalcrank assembly carried by said main frame such that said frontderailleur is movable along with movement of said chain stay member. 10.The bicycle frame of claim 1, wherein said main frame is configured tosupport a pedal crank assembly for rotation about a crank axis, saidpivot between said chain stay member and said main frame beingpositioned behind said crank axis.
 11. The bicycle frame of claim 1,wherein said main frame is configured to support a pedal crank assemblyfor rotation about a crank axis, said pivot between said chain staymember and said main frame being positioned a radial distance of lessthan about 3 inches from said crank axis.
 12. The bicycle frame of claim1, wherein said main frame is configured to support a pedal crankassembly for rotation about a crank axis, said pivot between said chainstay member and said main frame being positioned a radial distance ofless than about 2 inches from said crank axis.
 13. The bicycle frame ofclaim 1, wherein said main frame is configured to support a pedal crankassembly for rotation about a crank axis, said crank axis beingpositioned between about 4 and 12 inches from said second axis.
 14. Thebicycle frame of claim 1, wherein said main frame is configured tosupport a pedal crank assembly for rotation about a crank axis, saidcrank axis being positioned between about 5 and 7 inches from saidsecond axis.
 15. The bicycle frame of claim 1, wherein said first axisis positioned above said second axis in a relaxed position of saidarticulating frame.
 16. The bicycle frame of claim 1, wherein saidarticulating frame defines a hub axis, a rear wheel carried by saidarticulating frame being rotatable about said hub axis, saidarticulating frame being moveable relative to said main frame to provideat least 6 inches of vertical movement of said hub axis from a relaxedpositioned to a compressed position of said articulating frame.
 17. Thebicycle frame of claim 1, wherein said articulating frame defines a hubaxis, a rear wheel carried by said articulating frame being rotatableabout said hub axis, said articulating frame being moveable relative tosaid main frame to provide at least 8 inches of vertical movement ofsaid hub axis from a relaxed positioned to a compressed position of saidarticulating frame.
 18. A bicycle frame, comprising: a main frame, saidmain frame defining a steering axis of said bicycle frame and beingconfigured to support a front wheel for rotation about said steeringaxis; a chain stay member, said chain stay member being pivotallysupported relative to said main frame at a first pivot axis; a linkmember, said link member being pivotally supported by said main frame ata second pivot axis; a seat stay member, said seat stay member beingpivotally supported by said chain stay member at a third pivot axis andby said link member at a fourth pivot axis; a shock support member, saidshock support member being fixed for angular displacement with saidchain stay member, said shock support member defining a derailleur-mountportion configured to support a front derailleur in an operable positionrelative to a pedal crank assembly carried by said main frame; a shockabsorber, said shock absorber being pivotally supported by said shocksupport member at a fifth pivot axis and by said main frame at a sixthpivot axis.
 19. The bicycle frame of claim 18, wherein said shocksupport member comprises a first arm and a second arm extending fromsaid chain stay member toward said first axis, said first arm, saidsecond arm and said chain stay member cooperating to form a generallytriangular shape when viewed from the side of said bicycle frame. 20.The bicycle frame of claim 18, wherein said seat stay member isconfigured to support a rear wheel for rotation about a hub axis. 21.The bicycle frame of claim 20, wherein said third pivot axis ispositioned above said hub axis on said seat stay member.
 22. The bicycleframe of claim 18, wherein said chain stay member is configured tosupport a rear wheel for rotation about a hub axis.
 23. The bicycleframe of claim 18, wherein said first, second and sixth pivot axes aredefined by a monolithic portion of said main frame.
 24. The bicycleframe of claim 18, wherein said main frame is configured to support apedal crank assembly for rotation about a crank axis, wherein a radialdistance between said crank axis and said first pivot axis is less thanabout 3 inches.
 25. The bicycle frame of claim 18, wherein said mainframe is configured to support a pedal crank assembly for rotation abouta crank axis, wherein a radial distance between said crank axis and saidfirst pivot axis is less than about 2 inches.
 26. The bicycle frame ofclaim 18, wherein a longitudinal axis of said shock absorber passesthrough said fifth pivot axis and said sixth pivot axis, saidlongitudinal axis being angled in a downward direction from said fifthpivot axis to said sixth pivot axis.
 27. The bicycle frame of claim 18,wherein said fifth pivot axis is positioned above said sixth pivot axis.28. A bicycle, comprising: a front wheel; a rear wheel; a main frame,said main frame defining a steering axis of said bicycle frame and beingconfigured to support said front wheel for rotation about said steeringaxis; an articulating frame configured to support said rear wheelrelative to said main frame, said articulating frame comprising a chainstay member and a shock support member, said chain stay member beingpivotally supported relative to said main frame and said shock supportmember being fixed for angular displacement with said chain stay member;a shock absorber having a first end and a second end, said first endbeing pivotally supported at a first axis by said shock support memberand said second end being pivotally supported at a second axis by saidmain frame; wherein said first axis is positioned above said second axissuch that a longitudinal axis of said shock absorber slopes downwardlyfrom said first end to said second end.
 29. The bicycle of claim 28,wherein said main frame is configured to support a pedal crank assemblyfor rotation about a crank axis, said first axis being positioned behindsaid crank axis and said second axis being positioned in front of saidcrank axis.
 30. The bicycle of claim 28, wherein said shock supportmember comprises a first arm and a second arm extending from said chainstay member toward said first axis, said first arm, said second arm andsaid chain stay member cooperating to form a generally triangular shapein a side, elevational view of said bicycle.
 31. The bicycle of claim28, wherein said chain stay member is pivotally connected directly tosaid main frame.
 32. The bicycle of claim 28, wherein said articulatingframe additionally comprises a seat stay member and a link member, saidlink member being pivotally connected to said main frame and said seatstay member being pivotally connected to each of said chain stay memberand said link member.
 33. The bicycle of claim 32, wherein said rearwheel is supported for rotation about a hub axis, said hub axis beingdefined by said seat stay member.
 34. The bicycle of claim 33, whereinsaid pivotal connection between said chain stay member and said seatstay member is positioned above said hub axis on said seat stay member.35. The bicycle of claim 32, wherein said rear wheel is supported forrotation about a hub axis, said hub axis being defined by said chainstay member.
 36. The bicycle of claim 32, wherein said shock supportmember defines a derailleur-mount portion configured to support a frontderailleur in an operable position relative to a pedal crank assemblycarried by said main frame such that said front derailleur is movablealong with movement of said chain stay member.
 37. The bicycle of claim28, wherein said main frame is configured to support a pedal crankassembly for rotation about a crank axis, said pivot between said chainstay member and said main frame being positioned behind said crank axis.38. The bicycle of claim 28, wherein said main frame is configured tosupport a pedal crank assembly for rotation about a crank axis, saidpivot between said chain stay member and said main frame beingpositioned a radial distance of less than about 3 inches from said crankaxis.
 39. The bicycle of claim 28, wherein said main frame is configuredto support a pedal crank assembly for rotation about a crank axis, saidpivot between said chain stay member and said main frame beingpositioned a radial distance of less than about 2 inches from said crankaxis.
 40. The bicycle of claim 28, wherein said main frame is configuredto support a pedal crank assembly for rotation about a crank axis, saidpivot between said chain stay member and said main frame beingpositioned between about 4 and 12 inches from said second axis.
 41. Thebicycle of claim 28, wherein said main frame is configured to support apedal crank assembly for rotation about a crank axis, said pivot betweensaid chain stay member and said main frame being positioned betweenabout 5 and 7 inches from said second axis.
 42. The bicycle of claim 28,wherein said first axis is positioned above said second axis in arelaxed position of said articulating frame.
 43. The bicycle of claim28, wherein said articulating frame defines a hub axis, said rear wheelbeing rotatable about said hub axis, said articulating frame beingmoveable relative to said main frame to provide at least 6 inches ofvertical movement of said hub axis from a relaxed positioned to acompressed position of said articulating frame.
 44. The bicycle of claim43, wherein said articulating frame provides at least 8 inches ofvertical movement of said hub axis from a relaxed positioned to acompressed position of said articulating frame.